WO2010092674A1

WO2010092674A1 - Audio signal mixer

Info

Publication number: WO2010092674A1
Application number: PCT/JP2009/052314
Authority: WO
Inventors: 章服部
Original assignee: パイオニア株式会社
Priority date: 2009-02-12
Filing date: 2009-02-12
Publication date: 2010-08-19
Also published as: US20110317851A1; EP2398252A4; EP2398252A1; JP4855542B2; JPWO2010092674A1

Abstract

An audio signal mixer can be applied to a DJ device and the like, for example. The audio signal mixer acquires a plurality of audio signals and acquires mixing rate information being information on a mixing rate of a plurality of the audio signals. The audio signal mixer decides an adjusting amount of balance between levels at every band when a plurality of the audio signals are mixed based on the mixing rate. A plurality of the audio signals are mixed at every band, adjusts the levels of the mixed signals of the respective bands based on the adjusting amount, adds the adjusted signals of the respective bands and outputs it as a mixed audio signal.

Description

Audio signal mixing device

The present invention relates to an apparatus for mixing audio signals of a plurality of channels.

2. Description of the Related Art An audio signal mixing device is known that has a configuration of an audio mixer with two or more channels (CH) and performs long mixing of music in accordance with a user's crossfader operation designation (see, for example, Patent Document 1).

In the audio signal mixing apparatus as described above, a plurality of channels of audio signals are separately input to a DSP (Digital Signal Processor) inside the audio signal mixing apparatus, and a plurality of audio signals are mixed and output inside the DSP.

At this time, the audio signal mixing device performs level adjustment using the mixing ratio parameter based on the position information of the crossfader sent from the microcomputer inside the audio signal mixing device.

JP-A-8-195068

As described above, if the audio signal mixing device simply mixes audio signals of multiple channels based on the position of the crossfader, the user may hear the level of the sound mixed for each band differently. There is sex.

As a premise that the above phenomenon occurs, when mixing multiple songs using the above audio signal mixing device, the mixing operation is usually performed with the tempo and beat position of the songs to be mixed together in some way Need to be considered. In this case, the bass drum “dong” sound and the bass attack sound, where energy is concentrated in the low frequency range, are easily aligned in phase even between audio signals of different songs. When mixed in, the maximum volume is doubled. However, in the middle / high range, the audio signal is a different song, so the degree of correlation is low from the viewpoint of the spectrum distribution at a certain timing, and even if it is simply mixed, the volume feeling is not doubled. As a result, the mixed audio signal is uncomfortable to listen with a relatively low frequency emphasis.

Examples of problems to be solved by the present invention include the above. An object of the present invention is to provide an audio signal mixing apparatus capable of mixing a plurality of audio signals without losing balance between bands.

The invention according to claim 1 is an audio signal mixing device, wherein an audio signal acquisition means for acquiring a plurality of audio signals, a mixing ratio acquisition means for acquiring a mixing ratio of the plurality of audio signals, and the plurality of audio signals are acquired. An adjustment amount determining means for determining an adjustment amount of the level of each band when the audio signal is mixed at the mixing ratio, and the plurality of audio signals are mixed for each band at the mixing ratio, and the mixed signal for each band A signal mixing means for outputting, a level adjusting means for performing level adjustment for each band based on the adjustment amount, and a signal of each band adjusted by the level adjusting means for the mixed signal, Adding means for outputting as a mixed audio signal.

The invention according to claim 6 is an audio signal mixing method for mixing a plurality of audio signals, an audio signal acquiring step for acquiring a plurality of audio signals, and a mixing ratio for acquiring a mixing ratio of the plurality of audio signals. An acquisition step; an adjustment amount determination step for determining an adjustment amount of each band level when the plurality of audio signals are mixed at the mixing ratio; and the plurality of audio signals are mixed for each band at the mixing ratio. A signal mixing unit that outputs a mixed signal for each band; a level adjusting unit that performs level adjustment for each band based on the adjustment amount with respect to the mixed signal; and each band whose level is adjusted by the level adjusting unit And adding means for adding the signals to output as a mixed audio signal.

It is a physical structure figure of an audio signal mixing device. It is a block diagram which shows the structure inside DSP which concerns on 1st Example. It is a figure which shows the average level of various signal level values. It is a flowchart which shows the procedure of the audio signal mixing method. It is a block diagram which shows the structure inside DSP which concerns on 2nd Example. It is a block diagram which shows the structure inside DSP which concerns on 3rd Example.

Explanation of symbols

1 Audio signal mixing device 2 DSP
3 A / D converter 4 Microcomputer 5 Crossfader 6 D / A converter 8 Band division unit 9 Delay unit 21 Band division filter 22 Optimal mix level calculation unit 24 Band-specific level adjustment unit 25 Adder

In one aspect of the present invention, an audio signal mixing device includes an audio signal acquisition unit that acquires a plurality of audio signals, a mixing ratio acquisition unit that acquires a mixing ratio of the plurality of audio signals, and the plurality of audio signals. The adjustment amount determining means for determining the adjustment amount of the level of each band when mixing at the mixing ratio and the plurality of audio signals are mixed for each band at the mixing ratio, and a mixed signal is output for each band. A signal mixing unit, a level adjusting unit that performs level adjustment for each band based on the adjustment amount, and a signal of each band that has been level-adjusted by the level adjusting unit are added to the mixed signal. And adding means for outputting as follows.

The above audio signal mixing device can be applied to, for example, DJ equipment. The audio signal mixing apparatus acquires a plurality of audio signals, and acquires mixing ratio information that is information regarding a mixing ratio of the plurality of audio signals. The audio signal mixing apparatus determines an adjustment amount of the level of each band when a plurality of audio signals are mixed at a mixing ratio. Then, the audio signal mixing device mixes a plurality of audio signals for each band, adjusts the level of the mixed signal by the determined level adjustment amount, and adds the signals of each band after adjustment to add the mixed audio signal Output as.

In this way, the audio signal mixing device calculates the level adjustment amount of each band, adjusts the level balance between the bands based on the adjustment amount, and outputs a mixed signal of a plurality of audio signals. Therefore, this audio signal mixing device can provide a voice that does not feel uncomfortable for the user without an adjustment operation by the user.

One aspect of the audio signal mixing apparatus is configured to analyze frequency characteristics of the plurality of audio signals and obtain level information for each band, and each band when the plurality of audio signals are mixed at the mixing ratio. Level change rate calculating means for calculating the level change rate using level information for each band, and the adjustment amount determining means determines the adjustment amount based on the level change rate.

In this aspect, the frequency characteristics of a plurality of audio signals are analyzed, and the level change amount of each band when the signals are mixed is calculated. Then, the level adjustment amount is determined based on the level change amount. In this case, the audio signal mixing device analyzes the frequency characteristics of the audio signal acquired in real time and detects a change in the balance between the bands before and after mixing, so that a more appropriate adjustment amount can be calculated. It is possible to provide sound suitable for the user.

Another aspect of the audio signal mixing apparatus further includes beat position detecting means for detecting a beat position based on the plurality of audio signals, and the level adjusting means adjusts the level during a predetermined period including the beat position. I do. In this case, the audio signal mixing device generally detects a place where the level balance between the bands is likely to be broken, for example, a place where the low frequency level is increased by the beat detecting means, and the level around the location where the low frequency level is increased. Make adjustments. In other words, the audio signal mixing device calculates the adjustment parameter only when the level balance between the bands is likely to be lost, so that the balance between the bands is prevented from being lost, and the processing load of the adjustment parameter calculation and the level adjustment is reduced. Can be kept to a minimum.

In another aspect of the audio signal mixing device, level information acquisition means for acquiring level information for each band based on frequency characteristics of the plurality of audio signals, and the plurality of audio signals are mixed at the mixing ratio. Level change rate calculating means for calculating the level change rate of each band using level information for each band, and the adjustment amount determining means determines the adjustment amount based on the level change rate . In this case, since the audio signal mixing device does not need to perform frequency characteristic analysis, the processing load on the audio signal mixing device can be reduced.

In another aspect of the above audio signal mixing device, the adjustment amount determining means holds a predetermined adjustment amount. In this case, since the configuration of the audio signal mixing device is simplified, the audio signal mixing that can adjust the balance between bands even in a device centered on an analog circuit such as a DSP (Digital Signal Processor) that cannot use high-performance components. An apparatus can be realized.

In another aspect of the present invention, an audio signal mixing method for mixing a plurality of audio signals includes an audio signal acquisition step for acquiring a plurality of audio signals, and a mixing ratio acquisition step for acquiring a mixing ratio of the plurality of audio signals. An adjustment amount determining step for determining an adjustment amount of a level of each band when the plurality of audio signals are mixed at the mixing ratio; and mixing the plurality of audio signals for each band at the mixing ratio. A signal mixing means for outputting a mixed signal, a level adjusting means for adjusting a level for each band based on the adjustment amount for the mixed signal, and a signal of each band whose level is adjusted by the level adjusting means. Adding means for adding and outputting as a mixed audio signal.

Also by the above audio signal mixing method, the level adjustment amount of each band is calculated, and based on the adjustment amount, the signal level of each band is adjusted and a signal in which a plurality of audio signals are mixed is output. It is possible to provide a voice that does not feel uncomfortable for the user without going through the voice adjustment operation.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[Overview]
First, an outline of an audio signal mixing apparatus according to the present invention will be described. FIG. 1 schematically shows a basic configuration of the audio signal mixing device 1. As shown in the figure, the audio signal mixing device 1 includes a DSP (Digital Signal Processor) 2, A / D converters 3 A and 3 B, a microcomputer 4, a cross fader 5, and a D / A converter 6. Prepare.

When the audio signal mixing apparatus 1 acquires a two-channel audio reproduction signal from a CD (Compact Disk) player or the like (not shown), the A / D converters 3A and 3B convert the acquired audio reproduction signal into a digital signal, and the digital signal Send a signal to DSP2.

The microcomputer 4 acquires the position information of the crossfader operated by the user and sends the position information to the DSP 2.

When the DSP 2 acquires 2-channel digital signals from the A / D converters 3A and 3B and acquires cross-fader position information (hereinafter also referred to as “mixing ratio information”) from the microcomputer 4, first, For two-channel digital signals, the amount of adjustment of the level balance between the bands when they are mixed at the mixing ratio indicated by the mixing ratio information is determined. Next, the DSP 2 mixes the audio signals of two channels for each band based on the mixing ratio indicated by the mixing ratio information, and performs level adjustment on the mixed signal based on the adjustment amount. Then, the DSP 2 adds the signals of each band adjusted for balance, and outputs the added signal.

In this way, the audio signal mixing apparatus 1 detects the balance change between the bands before and after mixing of the two-channel audio signals and adjusts the balance between the bands, so that the music mix without any sense of incongruity is performed. be able to.

[First embodiment]
FIG. 2 shows a schematic configuration of the DSP 2A according to the first embodiment of the present invention. In this embodiment, two-channel audio signals S1 and S2 are input to the DSP 2A. Hereinafter, “channel” is also expressed as “CH”.

The audio signal S1, which is a signal of the input channel CH1, is input from the A / D converter 3A to the DSP 2 and supplied to the optimum mix level calculation unit 22 and the band division filter 21A. The audio signal S2, which is a signal of the input channel CH2, is input to the DSP 2 from the A / D converter 3B and supplied to the optimum mix level calculation unit 22 and the band division filter 21B.

Further, the mixing ratio information MP output from the microcomputer 4 is supplied to the optimum mix level calculation unit 22.

The optimal mix level calculation unit 22 performs frequency characteristic analysis for each of the audio signals S1 and S2, and calculates an average level for each band for the three bands of high frequency, middle frequency, and low frequency for the audio signal of each channel.

3A and 3B show a specific example in which the optimum mix level calculation unit 22 calculates the average level for each band of the audio signal of each channel. FIG. 3A is a diagram illustrating a result of frequency characteristic analysis performed on the audio signal S1 by the optimum mix level calculation unit 22, and FIG. 3B illustrates a frequency obtained by the optimum mix level calculation unit 22 regarding the audio signal S2. It is a figure which shows the result of having performed the characteristic analysis. In this case, the optimum mix level calculation unit 22 uses a high frequency average level H1 that is an average level of each of the high frequency, the middle frequency, and the low frequency as the average level for each band based on the frequency characteristic analysis result of the audio signal S1. The area average level M1 and the low area average level L1 are calculated. Moreover, the optimal mix level calculation part 22 calculates the high frequency average level level H2, the mid frequency average level M2, and the low frequency average level L2 as the average level for each band based on the frequency characteristic analysis result of the audio signal S2. The average level here may be an amplitude level, but is preferably calculated by an RMS (Root Mean Square) value (effective value).

Next, the optimum mix level calculation unit 22 generates a mixed signal by mixing the audio signals S1 and S2 in the entire band based on the mixing ratio information MP. FIG. 3C shows the result of frequency characteristic analysis performed on the mixed signal. Then, the optimum mix level calculation unit 22 calculates a low frequency average level L, a mid frequency average level M, and a high frequency average level H, which are average levels of the three bands of the mixed signal. Here, the low-frequency average level L, the mid-frequency average level M, and the high-frequency average level H indicate the levels of each band after the audio signals S1 and S2 are actually mixed.

Next, the optimum mix level calculation unit 22 mixes the high frequency mixing level LH obtained by mixing the high frequency average levels H1 and H2 at the above mixing ratio and the mid frequency average level M1 and M2 at the above mixing ratio. The obtained mid-range mixing level LM and the low-frequency mixing level LL obtained by mixing the low-frequency average levels L1 and L2 at the mixing ratio are calculated. Here, the high-frequency mixing level LH, the mid-frequency mixing level LM, and the low-frequency mixing level LL indicate the levels of the respective bands before the actual mixing of the audio signals S1 and S2.

Then, the optimum mix level calculation unit 22 calculates the level change rate (hereinafter, “level change rate”) before and after mixing the audio signals S1 and S2 for each band. Specifically, the optimum mix level calculation unit 22 calculates the ratio of the high frequency average level H to the high frequency mixing level LH as a high frequency level change rate: H / LH, and the mid frequency average level to the mid frequency mixing level LM The ratio of M is calculated as the mid-range level change rate: M / LM, and the ratio of the low-frequency average level L to the low-frequency mixture level LL is calculated as the low-frequency level change rate: L / LL. Then, the ratio of the high frequency level change rate, the mid frequency level change rate, and the low frequency level change rate is calculated as an inter-band change rate H / LH: M / LM: L / LL.

Now, assuming that the mixing ratio of the audio signal S1 and the audio signal S2 indicated by the mixing ratio information MP is I: J, the mixing coefficient A indicating the mixing ratio of the audio signal S1 can be expressed as A = I / (I + J). The mixing coefficient B indicating the mixing ratio of the signal S2 can be expressed as B = J / (I + J). Therefore, the high frequency mixing level LH, the mid frequency mixing level LM, and the low frequency mixing level LL are respectively
High frequency mixing level LH = A * H1 + B * H2
Mid-range mixing level LM = A * M1 + B * M2
Low frequency mixing level LL = A * L1 + B * L2
It becomes. The symbol “*” means multiplication.

Therefore, the change ratio between bands is
Band-to-band change ratio H / LH: M / LM: L / LL =
H / (A * H1 + B * H2): M / (A * M1 + B * M2): L / (A * L1 + B * L2)
It becomes.

The optimum mix level calculation unit 22 calculates the adjustment parameters Vh, Vm, and Vl for each band so that the change ratio between the bands is 1: 1: 1. Then, the optimum mix level calculation unit 22 sends the mixing ratio information MP and the adjustment parameters Vh, Vm, and Vl to the band-specific

level adjustment units

24H, 24M, and 24L.

Here, the reason why the adjustment parameters Vh, Vm, and Vl are calculated for each band so that the change ratio between the bands is 1: 1: 1 will be described. As described above, the high frequency level change rate H / LH indicates the change rate of the high frequency level before and after mixing the audio signals S1 and S2. Similarly, the mid-range level change rate M / LM indicates the rate of change of the mid-range level before and after mixing the audio signals S1 and S2, and the low-range level change rate L / LL is the mix of the audio signals S1 and S2. The change rate of the level of the low frequency before and after is shown. Therefore, if the adjustment parameters Vh, Vm, and Vl are determined so that the change ratio between the bands is 1: 1: 1, and the level of the mixed audio signal in each band is adjusted accordingly, the mixing of the audio signals S1 and S2 is adjusted. Before and after, the rate of change of the level of each band is maintained. That is, the level of each band after mixing is equal to the level of each band before mixing, and the balance of the levels of each band is maintained before and after mixing. Thereby, it is possible to prevent a problem that a specific band (generally, a low frequency band) is improperly emphasized due to mixing of audio signals.

On the other hand, the band division filters 21A and 21B divide the input audio signal into three bands, a high band, a middle band, and a low band, and adjust the level of each band of the high band component signal, the mid band component signal, and the low band component signal. The data is sent to the

units

24H, 24M and 24L.

Specifically, the band division filter 21A supplies the high-frequency component signal S1H of the audio signal S1 to the band-specific level adjustment unit 24H, and supplies the mid-frequency component signal S1M to the band-specific level adjustment unit 24M. S1L is supplied to the level adjusting unit 24L for each band. Similarly, the band division filter 21B supplies the high-frequency component signal S2H of the audio signal S2 to the band-specific level adjustment unit 24H, supplies the mid-frequency component signal S2M to the band-specific level adjustment unit 24M, and the low-frequency component signal S2L. Is supplied to the band-specific level adjusting unit 24L.

The level adjusting unit 24H for each band adjusts the level of the high frequency component of the audio signal, the level adjusting unit 24M for each band adjusts the level of the middle frequency component of the audio signal, and the level adjusting unit 24L for each band reduces the level of the audio signal. Adjust the level of the band component.

Specifically, the level adjusting unit 24H for each band acquires the high frequency component signal S1H of the audio signal S1 from the band division filter 21A and also acquires the high frequency component signal S2H of the audio signal S2 from the band division filter 21B. Further, the band-specific level adjustment unit 24H acquires the mixing ratio information MP and the adjustment parameter Vh from the optimum mix level calculation unit 22. Then, the level adjusting unit 24H for each band mixes the high frequency component signal S1H of the audio signal S1 and the high frequency component signal S2H of the audio signal S2 at a mixing ratio (I: J) indicated by the mixing ratio information MP, and mixes them. The signal is multiplied by the adjustment parameter Vh.

The level adjusting unit 24M for each band acquires the middle band component signal S1M of the audio signal S1 from the band division filter 21A and also acquires the middle band component signal S2M of the audio signal S2 from the band division filter 21B. Further, the band-specific level adjustment unit 24M acquires the mixing ratio information MP and the adjustment parameter Vm from the optimum mix level calculation unit 22. Then, the level adjusting unit 24M for each band mixes the middle band component signal S1M of the audio signal S1 and the middle band component signal S2M of the audio signal S2 at the mixing ratio indicated by the mixing ratio information MP, and adjusts the mixed signal. Multiply the parameter Vm.

Similarly, the band-specific level adjusting unit 24L acquires the low frequency component signal S1L of the audio signal S1 from the band division filter 21A and also acquires the low frequency component signal S2L of the audio signal S2 from the band division filter 21B. Further, the band-specific level adjustment unit 24L acquires the mixing ratio information MP and the adjustment parameter Vl from the optimum mix level calculation unit 22. Then, the level adjusting unit 24L for each band mixes the low frequency component signal S1L of the audio signal S1 and the low frequency component signal S2L of the audio signal S2 at the mixing ratio indicated by the mixing ratio information MP, and adjusts the mixed signal. Multiply the parameter Vl.

As described above, the band-specific

level adjusting units

24H, 24M, and 24L mix the components of the respective bands of the audio signals S1 and S2 at the mixing ratio indicated by the mixing ratio information MP, and then adjust the adjustment parameters Vh determined for each band. The level of the mixed signal is adjusted based on Vm and Vl. Here, as described above, the adjustment parameters Vh, Vm and Vl of each band are determined so that the change ratio between the bands is 1: 1: 1. Therefore, the signal level of each band after the level adjustment is The signal level balance of each band before mixing is maintained.

The adder 25 adds the mixed signals of the respective bands output from the band-specific

level adjusting units

24H, 24M, and 24L, and outputs the result as a mixed audio signal.

Thus, the audio signal mixing device calculates the adjustment parameter for each band so as to maintain the level balance between the bands before and after mixing the signals, and adds the signal whose level is adjusted with the adjustment parameter for each band. Output as a mixed audio signal. According to this, the audio signal mixing apparatus can generate a mixed audio signal that maintains a level balance between bands.

In the above configuration, the optimum mix level calculation unit 22 functions as a mixing ratio acquisition unit, an adjustment amount determination unit, a level change rate calculation unit, an analysis unit, and a level information acquisition unit in the present invention. The band-specific

level adjusting units

24H, 24M and 24L function as signal mixing means and level adjusting means in the present invention, and the adder 25 functions as adding means in the present invention.

[Audio signal mixing method according to first embodiment]
Next, the audio signal mixing method according to the first embodiment will be described with reference to the flowchart shown in FIG.

First, the microcomputer 4 detects the position of the crossfader 5, and when the position of the crossfader 5 is the mix position (step S101; Yes), the microcomputer 4 converts the position information of the crossfader 5 into the mixing ratio information MP. To the DSP 2 (step S102). The mix position here refers to a position other than both ends of the crossfader.

The DSP 2A acquires the audio signal of each channel (step S103), and the optimal mix level calculation unit 22 in the DSP 2A performs frequency characteristic analysis on the audio signal (step S104).

Then, the optimum mix level calculation unit 22 calculates the average level of the three bands of high frequency, mid frequency and low frequency for the audio signal of each channel (step S105). Specifically, the optimum mix level calculation unit 22 calculates the high frequency average level H1, the mid frequency average level M1, and the low frequency average level L1 for the audio signal S1, and the high frequency average level H2 and the mid frequency for the audio signal S2. An average level M2 and a low frequency average level L2 are calculated.

Next, the optimal mix level calculation unit 22 generates a mixed signal by mixing the audio signals of the respective channels at the mixing ratio (I: J) indicated by the mixing ratio information MP (step S106).

Next, the optimum mix level calculation unit 22 performs frequency characteristic analysis on the mixed signal (step S107), and the low frequency average level L, the mid frequency average level M, and the high frequency average that are the average levels of the three bands of the mixed signal. Level H is calculated (step S108).

Then, the optimum mix level calculation unit 22 calculates the interband change ratio H / LH: M / LM: L / LL (step S109) and adjusts the adjustment parameter Vh so that the interband change ratio is 1: 1: 1. Vm and Vl are calculated (step S110), and the adjustment parameters are sent to the band-specific

level adjustment units

24H, 24M, and 24L.

On the other hand, the band division filter 21A and the band division filter 21B divide each input signal into three bands, and send the signals in each band to the band-specific

level adjustment units

24H, 24M, and 24L (step S111).

The band-specific

level adjusting units

24H, 24M, and 24L mix the acquired signals at the mixing ratio (I: J) indicated by the mixing ratio information MP (step S112). Then, each of the band

level adjusting units

24H, 24M, and 24L multiplies the mixed signals by adjustment parameters Vh, Vm, and Vl (step S113). The adding unit 25 adds the signals output from the

level adjusting units

24H, 24M, and 24L for each band (step S114), outputs the signals as mixed audio signals for the entire region (step S115), and ends the process.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 5 shows a schematic configuration in the DSP 2B of the audio signal mixing device 1 according to the second embodiment. In addition, the same code | symbol is attached | subjected to the component same as DSP2A of 1st Example shown in FIG. 1, and the description is abbreviate | omitted.

The DSP 2B of the audio signal mixing device 1 according to the second embodiment includes the BPM detection unit 26, but the other points are basically the same as the DSP 2A of the first embodiment. The BPM detector 26 functions as a beat detector in the present invention.

The BPM detection unit 26 detects the BPM (Beat Per Minute) of the audio signal S2. Specifically, the BPM detection unit 26 detects the position of the beat in the audio signal S2, for example, a portion where the low frequency level rises at a stroke, and notifies the optimum mix level calculation unit 22 of it. The optimal mix level calculation unit 22 sets a certain time including the position of the beat as the adjustment target period, and based on the audio signal S1 and the audio signal S2 in the adjustment target period, in the same manner as in the first embodiment, the interband change ratio The adjustment parameters Vh, Vm, and Vl are generated so that becomes 1: 1: 1. The optimal mix level calculation unit 22 sets all the adjustment parameters Vh, Vm, and Vl to “1” in a period other than the adjustment target period. The optimum mix level calculation unit 22 sends the adjustment parameters Vh, Vm, and Vl generated in this way to the band-specific

level adjustment units

24H, 24M, and 24L.

As described above, in the second embodiment, the BPM detection unit 26 detects the beat position where the level balance between the bands is likely to be lost before and after the signal mixing, and in the adjustment target period around the beat position. Only level adjustment using adjustment parameters is performed. On the other hand, during the period other than the adjustment target period, all adjustment parameter values are set to “1”, and level adjustment is not substantially performed. That is, in the second embodiment, the audio signal mixing device 1 calculates the adjustment parameter and performs the level adjustment for each band only when the level balance between the bands is likely to be lost, and does not perform the level adjustment in other periods. . Therefore, it is possible to minimize the burden of the adjustment parameter calculation processing and the level adjustment processing for each band while preventing the level balance between the bands from being lost before and after mixing the signals.

[Third embodiment]
Next, a third embodiment of the present invention will be described. FIG. 6 shows a schematic configuration of the DSP 2C in the audio signal mixing device 1 according to the third embodiment. In addition, the same code | symbol is attached | subjected to the component same as the audio signal mixing apparatus 1 of 1st Example shown in FIG. 1, and the description is abbreviate | omitted. The DSP 2C of the audio signal mixing device 1 according to the third embodiment omits the optimum mix level calculation unit 22 in the DSP 2A of the first embodiment.

In the third embodiment, the band-specific

level adjusting units

24H, 24M, and 24L are predetermined for each band with respect to the mixed signal after mixing the audio signals S1 and S2 for each band based on the mixing ratio information MP. The adjustment parameter (hereinafter referred to as “default adjustment parameter”) is multiplied. And the adder 25 adds the signal which multiplied the default adjustment parameter for every band, and outputs it as a mixed audio signal.

Here, an example of determining the default adjustment parameters will be described. Considering a plurality of audio signals to be mixed, generally, low-frequency components have a relatively high correlation, and therefore a certain level of increase is expected when mixed. On the other hand, since the correlation between the mid and high frequency components is lower than that of the low frequency components, the increase in the level when mixed is considered to be small compared to the low frequency components. Therefore, it is assumed that the level of the low frequency component is increased by about 6 dB and the level of the middle / high frequency component is increased by about 3 dB, and the level of the low frequency component is lowered by about 3 dB from the level of the middle / high frequency component. Determine default tuning parameters. Thereby, the level balance for every zone | band after mixing of a signal is maintainable. In addition, said value is a mere example and can be suitably determined according to the kind etc. of the music to mix.

In the case of the audio signal mixing apparatus 1 of the third embodiment, unlike the first and second embodiments, the level for each band is determined by the default adjustment parameter determined in advance without analyzing the audio signal to be mixed. Adjustments are made. As a result, the configuration of the apparatus is simplified, and an audio signal mixing apparatus capable of adjusting the level balance between bands can be realized even in an analog circuit-centric apparatus that cannot use high-performance components such as a DSP. .

As described above, the audio signal mixing apparatus 1 of the present invention outputs a mixed audio signal after adjusting the balance between levels for each band when a plurality of audio signals are mixed. Can output a mixed audio signal that is comfortable for the user.

The audio signal mixing apparatus according to the prior art is capable of smoothly mixing with one operator while adjusting the level of music pieces to be mixed according to the position of the operator, but in reality, a disc jockey (DJ ), Etc. are often mixed with this operation element so as to connect the music pieces by lowering the low frequency level of any music piece with an equalizer knob or the like so as not to interfere. This is a technique that a DJ who has a sense of discomfort naturally wears because the sound pressure difference for each band changes due to mixing and the sound pressure in a relatively low range increases and sounds. However, in order to perform mixing with less uncomfortable feeling more easily, the level may be corrected by detecting the level change rate for each band before and after mixing signals as in the present invention. Thereby, the mix play without a sense of incongruity is attained by one operation element.

[Modification]
In the first embodiment described above, the method of calculating the average level of each band by performing frequency characteristic analysis on the input signal in real time has been described. However, the present invention is not limited to this, and from other PCs (personal computers), etc. You may make it acquire the data of the frequency characteristic acquired beforehand. In this case, since the audio signal mixing device 1 does not need to perform frequency characteristic analysis, the processing load on the device can be reduced.

In the above-described embodiments, the case where the audio signal is divided into three bands has been described. However, the present invention is not limited to this, and the audio signal to be mixed is divided into two or four or more bands. Then, the level balance between the bands may be adjusted.

Moreover, although the audio signal mixing apparatus 1 described the case where two audio signals are mixed in the above-described embodiment, the present invention is not limited to this, and three or more audio signals may be mixed. .

In the above-described embodiment, the crossfader is used for the user to specify and input the mixing ratio. However, the present invention is not limited to this, and the user specifies the mixing ratio by various other operations. You may do it.

The present invention can be used when a plurality of audio signals are mixed in a DJ device, a sound business mixer, a home recording device, or a PC application.

Claims

Audio signal acquisition means for acquiring a plurality of audio signals;
Mixing ratio acquisition means for acquiring a mixing ratio of the plurality of audio signals;
An adjustment amount determining means for determining an adjustment amount of the level of each band when the plurality of audio signals are mixed at the mixing ratio;
The signal mixing means for mixing the plurality of audio signals for each band at the mixing ratio and outputting a mixed signal for each band;
Level adjustment means for performing level adjustment for each band based on the adjustment amount for the mixed signal;
An audio signal mixing apparatus comprising: adding means for adding the signals of the respective bands whose levels have been adjusted by the level adjusting means and outputting them as mixed audio signals.
Analyzing means for analyzing frequency characteristics of the plurality of audio signals and obtaining level information for each band;
Level change rate calculating means for calculating a level change rate of each band when the plurality of audio signals are mixed at the mixing ratio, using level information for each band; and
The audio signal mixing apparatus according to claim 1, wherein the adjustment amount determination unit determines an adjustment amount based on the level change rate.
Beat position detecting means for detecting a beat position based on the plurality of audio signals,
The audio signal mixing apparatus according to claim 2, wherein the level adjustment unit performs level adjustment in a predetermined period including the beat position.
Level information acquisition means for acquiring level information for each band based on frequency characteristics of the plurality of audio signals;
Level change rate calculating means for calculating a level change rate of each band when the plurality of audio signals are mixed at the mixing ratio, using level information for each band; and
The audio signal mixing apparatus according to claim 1, wherein the adjustment amount determination unit determines an adjustment amount based on the level change rate.
2. The audio signal mixing apparatus according to claim 1, wherein the adjustment amount determination means holds a predetermined adjustment amount.
An audio signal mixing method for mixing a plurality of audio signals,
An audio signal acquisition step of acquiring a plurality of audio signals;
A mixing ratio acquisition step of acquiring a mixing ratio of the plurality of audio signals;
An adjustment amount determining step for determining an adjustment amount of the level of each band when the plurality of audio signals are mixed at the mixing ratio;
Signal mixing means for mixing the plurality of audio signals for each band at the mixing ratio, and outputting a mixed signal for each band;
Level adjustment means for performing level adjustment for each band based on the adjustment amount for the mixed signal;
An audio signal mixing method comprising: adding means for adding signals of respective bands whose levels have been adjusted by the level adjusting means and outputting the signals as mixed audio signals.